Safety device for hypodermic needle or the like

ABSTRACT

A safety device for a hypodermic needle or for a similar instrument used in the clinical puncture of the skin comprises a sheath (6, 25 or 32) adapted to be connected to the needle (5, 21 or 33) or to a support (4 or 31) for the needle. The sheath is so connected in a first position (FIGS. 1A, 2A, or 3A) which permits normal use of the needle and can be placed, by movement relative to the needle (FIGS. 1B or 3B) or by folding upon itself (FIGS. 2B and 2C) in a second position in which the needle is encapsulated by the sheath. The sheath is retained in that second position, for example by a projection (9, 27 or 35) extending into a slot (10 or 36) or through an aperture (28).

This is a continuation of Ser. No. 08/160,859 filed Dec. 3, 1993.Iadd.(now U.S. Pat. No. 5,601,535).Iaddend., which is a continuation ofSer. No. 07/709,999 filed Jun. 4, 1991 .Iadd.(now abandoned).Iaddend.,which a continuation of Ser. No. 07/595,664 filed Oct. 11, 1990 (nowU.S. Pat. No. 5,084,030), which is a continuation of 07/241,256 filedSep. 7, 1988 (now abandoned), which is a continuation of Ser. No.06/888,376 filed Jul. 23, 1986 (now U.S. Pat. No. 4,826,490).

The present invention is a safety device for a hypodermic needle orsimilar instrument used in the clinical puncture of the skin.

The taking of blood samples from persons in hospitals, health centres orother clinical areas is a routine medical procedure, as is the injectionof pharmnaceutical preparations or biological materials. However, manyincidents have been reported in the press and in medical journals ofclinical operators subsequently accidentally wounding themselves orother persons with the needle and thereby either transmitting a diseaseor causing chemical or biological poisoning.

There is a clear need for a device which permits the disposal of ahypodermic needle or such instrument in a manner which protects theclinical operator, observers of the clinical procedure and all otherpersons concerned, including the general public, from accidentalwounding.

It is an object of the present invention to provide such a device.

The safety device according to the invention for a hypodermic needle orsimilar instrument comprises a sheath, adapted to be connected to saidneedle or other instrument or to a support therefor in a first positionwhich permits normal use of said needle or other instrument and to beplaceable, by movement relative to the needle or other instrument or byfolding upon itself, in a second position in which the needle or otherinstrument is encapsulated by the sheath and the sheath is retained inthat second position.

As indicated, the safety device of the present invention is generallyapplicable to the protection of puncturing instruments typified byhypodermic needles, although among such instruments hypodermic needlesare by far the most widely used. For example, the device may be appliedto the protection of biopsy needles, winged needles, that is needlesprovided with lateral attachments to enable them to be affixed to theskin surface as by adhesive tape, and to intravenous cannulas and lumbarpuncture needles. For convenience, the invention is hereinafterdescribed specifically as applied to "needles", in particular hypodermicneedles, but it is emphasised that the invention is not to be limitedthereby.

The sheath is adapted to be attached to the needle or to a support forthe needle but may be provided separately from the needle, to beattached to the needle or support at the point of use, either before orafter the needle has actually been used It is much preferred that suchseparate sheaths be attached before use, so that the needle may be morereadily encapsulated immediately after it has been used. However, thesheath according to the present invention is preferably and convenientlysupplied already attached to the needle. In particular, it is preferablyattached either irremovably or in a way which makes its removaldiificult. For example, the sheath may be adhered to the needle or to asupport for the needle or may be clipped to the needle or support.

When the needle is designed for use without a syringe or remote from anassociated syringe, to which it is then linked by a flexible tube, thenthe sheath is preferably secured direct to the needle. The sheath maythen conveniently incorporate one or more parts which are foldablerelative to the body of the sheath and thereby to encapsulate theneedle.

When the needle, on the other hand, is mounted upon a housing designedto be attached to a syringe barrel or luer connector, then the sheathmay advantageously be secured to the housing. The sheath may then becapable of movement relative to the housing in a direction which has acomponent parallel to the length of the needle, so that the sheath maybe moved along the length of the needle until the latter is fullyencapsulated. This relative movement of sheath and housing may forexample be a linear sliding movement or a spiral movement, as moreparticularly exemplified hereinafter in FIGS. .[.3A.]. .Iadd.2A.Iaddend.and .[.3B.]. .Iadd.5A .Iaddend.of the drawings.

Such relative movement of sheath and housing may be determined by one ormore linear or spiral grooves or channels in the housing engaging one ormore lugs or other projections on the sheath--or grooves or channels inthe sheath engaging projections on the housing.

In the second position of the sheath, in which the needle isencapsulated, the sheath is retained against further movement relativeto the needle. That retaining of the sheath is preferably irreversibleor reversible only with difficulty. For example, one or more lugs orother projections on one of the relatively movable components may engageone or more apertures or slots in the other component, preferably underthe pressure of a natural resilience in at least one of the componentsor under pressure from one or more springs.

The sheath may advantageously and conveniently be made from a resilientplastics material, for example polypropylene, and the housing may bemade from the same, or a similar, material.

The invention will now be further described with reference to theaccompanying drawings, wherein:

FIG. 1A is a sectional view of a first embodiment of the safety deviceaccording to the present invention, in a position in which the needlemay be used normally;

FIG. 1B is an enlarged detailed view of the circled portion of FIG. 1A;

FIG. 2A is a view corresponding to that of FIG. 1A but with the sheathmoved to encapsulate the needle;

FIG. 2B is an enlarged detailed view of the circled portion of FIG. 2A;

FIG. 3 is a sectional view of a second embodiment of the safety deviceaccording to the present invention, in a position in which the needlemay be used normally;

FIG. 4A is a view corresponding to that of FIG. 3 but with the sheathfolded to encapsulate the needle;

FIG. 4B is an enlarged view of the circled portion of FIG. 4A;

FIG. 4C is a plan view of the device in the position shown in FIG. 4A;

FIG. 5A is a view, partly in section of a third embodiment of the safetydevice according to the present invention, in a position in which theneedle may be used normally;

FIG. 5B is a view corresponding to that of FIG. 5A but with the sheathmoved to encapsulate the needle;

FIG. 5C is an enlarged view of the circled portion of FIG. 5B.[...]..Iadd.;

New FIG. 6 is a view similar to FIG. 5B illustrating a further form ofthe guide slot and projection. .Iaddend.

The embodiment of the invention shown in FIGS. 1A and 1B comprises aneedle housing 4 in the form of a plastics moulding carrying a needle 5and, slidably supported upon the housing 4, a plastics sheath 6incorporating a thumb guard 7 integral therewith. .Iadd.The thumb guard7 constitutes a lateral enlargement of the guard and as illustrated inFIG. 2A has an arcuate surface 7a providing a finger-engaging surface.The needle housing 4 thus comprises a hollow support structure and formswith needle 5 a sub-assembly. .Iaddend.Also incorporated in the housing4 and running length-wise, is a channel 8. The sheath 6 incorporates aself-springed spigot 9, which slides along the channel 8, as shown inmore detail in the enlarged inset. When the sheath travels to the end ofthe channel 8, the self-springed spigot 9 drops into a small "well" 10,thus locking the sliding sheath in position. The length of the sheath issuch that, when it is locked in position, the sharp end of the needle iscompletely enclosed by the sheath, as shown in FIG. 1B.

The housing 4 is designed to mate with any standard syringe barrel orluer connector. After use, the protective sheath is extended into thelocked position, thus encapsulating the needle in a safe manner.

The embodiment of the invention shown in FIGS. .[.2A to 2C.]. .Iadd.3and 4A-4C .Iaddend.is designed to allow encapsulation of a hypodermicneedle 21 which is tethered to a syringe (not shown) by an extensiontube 22. The needle 21 is sandwiched between two plastics mouldings orpressings 23,24 which together form a sheath 25. A part 26 of the sheath25 is permanently attached to the hypodermic needle. At points 23a and24a the plastic is formed in a manner which allows the free ends ofmembers 23 and 24 to hinge as indicated Near to its outer end, themember 23 carries two spigots 27, which are designed to mate with holes28 in the member 24 (when the sheath is in its folded position) and lockthe sheath securely around the needle 21.

The third embodiment of the invention, as illustrated in FIGS. .[.5A and5B.]. .Iadd.5A-5C.Iaddend., comprises a needle housing 31 in the form ofa plastics moulding, a plastics sheath 32 which is free to rotatethereon and a needle 33. Impressed into the housing 31 is helical groove34 extending from near the end of the housing 31 which is distal to theneedle 33 towards the needle. The sheath 32 has a self-springed spigot35 which fits into, and is free to move along, the helical groove 34.Iadd.while subject to a biasing force acting between the sheath 32 andhousing 31 during relative movement of the sheath and housing.Iaddend..As shown in FIG. .[.3B.]. .Iadd.5B.Iaddend., rotation of the sheath 32in a clockwise direction (viewed from the rear) will result in a forwardmotion causing the sheath to encapsulate the needle 33. At the end ofits travel the springed spigot 35 drops into a "well" 36 thereby lockingthe sheath in position. The length of the sheath 32 is such that when ithas reached this locked position the needle is completely encapsulatedand withdrawn beyond the orifice 37 in the outer end of the sheath.

The device shown in FIGS. .[.3A and 3B.]. .Iadd.5A-5C .Iaddend.isdesigned to mate with any standard syringe barrel or luer connector..Iadd.For example, as illustrated in FIG. 2A, a connector formation isprovided on an elongate body 40 including a tapered abutment surface 42for mating with the needle support housing and having a complementarytapered abutment surface 44.Iaddend.. After use, the protective sheathis placed in position by applying a twisting force to the sheath. Tofacilitate the application of this twisting force, a raised section 38may be incorporated into the sheath's surface.

This form of the invention may be fabricated with one or more helicalgrooves, which may extend in a clockwise or anti-clockwise direction.For greater mechanical strength and stability, a double helix may bepreferred.

.Iadd.In FIG. 6, the groove 34a and spigot 35a are formed in the sheath32a and housing 31a, respectively, i.e., reversed as previouslydescribed from the configuration of FIGS. 5A-5C. .Iaddend.

We claim:
 1. For use with clinical apparatus operably applicable to apatient by way of a deliberate skin puncture, a needle assembly operableto effect said skin puncture and comprising:a support structure; aneedle fixedly mounted in said structure to form therewith asub-assembly, with one end portion of said needle projecting from saidstructure, and said one end portion terminating in a skin-puncturingtip; a guard mounted around part of said sub-assembly for movementrelative thereto in the longitudinal direction of said needle from afirst position in which said tip is exposed to effect said deliberatepuncture, to a second position in which said tip is embraced by saidguard to prevent unintended skin puncture; a locking mechanism includingfirst and second elements, said first element being a projection fromone of said sub-assembly and guard, said second element being a stopsurface defining a space bordering the other of said sub-assembly andguard, said elements each extending transversely of said needlelongitudinal direction, said elements being spaced apart in saidlongitudinal direction when said guard is in said first position, saidprojection being subject to a bias force acting between saidsub-assembly and guard during said relative movement, and saidprojection being automatically irreversibly moved into said spacealongside said stop surface in response to said bias force when saidguard is in said second position to inhibit a returning relativemovement thereof towards said first position; and a stop mechanismeffective to constrain said guard from movement towards and around saidapparatus.
 2. An assembly according to claim 1 wherein said lockingmechanism second element stop surface defines said space as a recess inthe other of said sub-assembly and guard.
 3. An assembly according toclaim 1 wherein, to serve as said stop mechanism, said support structurehas a portion with external dimensions transversely of said longitudinaldirection which are enlarged relative to the remainder of the structure,and said guard has lesser corresponding internal transverse dimensionsaround said structure than said portion.
 4. For use with clinicalapparatus operably applicable to a patient by way of a deliberate skinpuncture, a needle assembly operable to effect said skin puncture andcomprising:a support structure; a needle fixedly mounted in saidstructure to form therewith a sub-assembly, with one end portion of saidneedle projecting from said structure, and said one end portionterminating in a skin-puncturing tip; a guard mounted around part ofsaid sub-assembly for movement relative thereto in the longitudinaldirection of said needle from a first position in which said tip isexposed to effect said deliberate puncture, to a second position inwhich said tip is embraced by said guard to prevent unintended skinpuncture; a locking mechanism including first and second elements, saidfirst element being a projection from one of said sub-assembly andguard, said second element being a stop surface defining a spacebordering the other of said sub-assembly and guard, said elements eachextending transversely of said needle longitudinal direction, saidelements being spaced apart in said longitudinal direction when saidguard is in said first position, said projection being subject to a biasforce acting between said sub-assembly and guard during said relativemovement, and said projection being automatically irreversibly movedinto said space alongside said stop surface in response to said biasforce when said guard is in said second position to inhibit a returningrelative movement thereof towards said first position; a stop mechanismeffective to constrain said guard from movement towards and around saidapparatus; said stop mechanism including a portion of said supportstructure having external dimensions transversely of said longitudinaldirection which are enlarged relative to the remainder of the structure,and said guard having lesser corresponding internal transversedimensions around said structure than said portion; said supportstructure having a connector formation for removable attachment withsaid clinical apparatus, which formation includes said transverselyenlarged portion. .Iadd.
 5. For use with clinical apparatus operablyapplicable to a patient by way of a deliberate skin puncture, a needleassembly operable to effect said skin puncture and comprising:a hollowsupport structure; a needle fixedly mounted on said structure adjacentone end thereof to form therewith a sub-assembly, with one end portionof said needle projecting from said structure, and said one end portionterminating in a skin puncturing tip having an opening therein, theneedle being longitudinal hollow to provide a direct fluid flow pathwayextending therethrough between said opening in said tip and theremainder of said needle from said one end portion, the needle having noobstruction therein along the entire length of said pathway so thatdirect fluid flow along the entire length of the pathway is permitted;said support structure including a connector formation at an oppositeend thereof from said needle to engage, in use of said needle assembly,with the clinical apparatus, said connector formation being integralwith said support structure and having an opening therethrough incommunication through said support structure with said pathway throughsaid needle; a guard mounted for movement relative to said sub-assemblyand in a longitudinal direction of said needle between a first positionin which said tip is exposed to effect said deliberate skin puncture anda second position in which said guard extends in part longitudinallybeyond said tip to prevent unintended skin puncture; said guard beingcarried by said sub-assembly in a captive manner to stop separation ofsaid guard from said sub-assembly by movement from said first positionin the longitudinal direction away from said second position; aprojection carried by said guard and projecting generally laterally ofthe longitudinal direction of said needle, said projection engaging saidsub-assembly during said relative movement of said guard and saidsub-assembly from said first position towards said second position; saidprojection being subject to a biasing force acting between said guardand part of said sub-assembly during said relative movement of saidguard and said sub-assembly; said projection being automaticallydisplaced in a general lateral direction in response to said relativemovement of said guard and said sub-assembly to lock said guard and saidsub-assembly in said second position. .Iaddend..Iadd.
 6. An assemblyaccording to claim 5 wherein said sub-assembly includes a guide forguiding said projection along said sub-assembly and throughout theextent of said relative movement of said guard and said sub-assemblyfrom said first position to said second position. .Iaddend..Iadd.7. Anassembly according to claim 6 wherein said guide includes a grooveformed in said sub-assembly. .Iaddend..Iadd.8. An assembly according toclaim 5 wherein said projection is subject to said biasing forcethroughout the extent of said relative movement of said guard and saidsub-assembly from said first position to said second position..Iaddend..Iadd.9. An assembly according to claim 5 wherein saidprojection engages said sub-assembly in said second position of saidguard and said sub-assembly. .Iaddend..Iadd.10. An assembly according toclaim 5 wherein said projection is subject to said biasing forcethroughout the extent of said relative movement of said guard and saidsub-assembly from said first position to said second position, saidprojection engaging said sub-assembly in said second position of saidguard and said sub-assembly. .Iaddend..Iadd.11. For use with clinicalapparatus operably applicable to a patient by way of a deliberate skinpuncture, a needle assembly operable to effect said skin puncture andcomprising:an elongated support structure having first and second endsand a first direct fluid flow pathway between said ends, said first endadapted for connection and fluid communication with the clinicalapparatus: a needle fixedly mounted adjacent said second end of saidstructure to form therewith a sub-assembly, one end portion of saidneedle projecting from said structure and terminating in a skinpuncturing tip having an opening therein, the needle beinglongitudinally hollow to provide a second direct fluid flow pathwayextending therethrough between said opening in said tip and theremainder of said needle from said one end portion and in opencommunication with said first pathway to form a continuous direct fluidflow pathway between said support structure first end and said openingin said tip, the needle and said support structure having no obstructiontherein along the entire length of said continuous pathway so thatdirect fluid flow along the entire length of said continuous pathway ispermitted; a guard mounted for movement relative to said sub-assemblyand in a longitudinal direction of said needle between a first positionin which said tin is exposed to effect said deliberate skin puncture anda second position in which said tip is enclosed by said guard to preventunintended skin puncture; said guard being carried by said sub-assemblyin a captive manner to stop separation of said guard from saidsub-assembly by movement from said first position in the longitudinaldirection away from said second position; a projection carried by one ofsaid sub-assembly and said guard and projecting generally laterally ofthe longitudinal direction of said needle; a guide slot extending alongat least one side of another of said sub-assembly and said guardgenerally in the longitudinal direction of the needle and terminating atone end in a recess having a stop surface; said projection engaging insaid slot in said first position of said guard and said sub-assembly andengaging along said slot during said relative movement of said guard andsaid sub-assembly from said first position to said second position; saidprojection extending into said recess upon said relative movement ofsaid guard and said sub-assembly into said second position andengageable against said stop surface to prevent relative movement ofsaid guard and said sub-assembly from said second position toward saidfirst position; said guard in said second position extending in partlongitudinally beyond said needle tip and enclosing said needle tip..Iaddend..Iadd.12. An assembly according to claim 11 including a lateralenlargement of said guard adjacent an end thereof remote from saidneedle in said second position of said guard. .Iaddend..Iadd.13. Anassembly according to claim 12 wherein said enlargement has an arcuatesurface providing a finger-engaging surface. .Iaddend..Iadd.14. Anassembly according to claim 11 wherein said projection and said anotherof said guard and said sub-assembly are subject to a biasing forcesubstantially throughout the extent of relative movement of said guardand said sub-assembly from said first position to said second positionenabling said projection to engage said stop surface in said secondposition of said guard and said sub-assembly to prevent said movementfrom said second position toward said first position. .Iaddend..Iadd.15.An assembly according to claim 11 wherein said guide slot is formedalong said guard and said projection projects from said sub-assembly..Iaddend..Iadd.16. An assembly according to claim 11 wherein said guideslot is formed along said sub-assembly and said projection projects fromsaid guard. .Iaddend.